I haven't used my Droid X warranty at all yet, so I'm not an "expert" on the matter by any means. However, I think this question can be solved without contacting Verizon... simply by thinking about the question and how the warranty works.

The warranty on the Droid phones is a warranty that is provided, and supported, by Motorola (or HTC depending on which Droid you have). It is a warranty against poor workmanship and/or defects that should not occur under normal use.

It is not a warranty provided by Verizon. Verizon does not manufacture the phones, they simply provide the services, sell the phones, etc. The only "warranty" (not a true warranty) that is provided THROUGH Verizon is the Asurion insurance. Even this is not provided BY Verizon, but rather by Asurion... and it is just sold/provided THROUGH Verizon.

The difference between this and the regular Motorola Droid warranty is the fact that the Asurion insurance covers literally just about anything. If your phone gets stolen, lost, screen gets cracked, or anything else along those lines... you can get a replacement phone simply for the cost of the deductible (which depends on the phone). With this insurance, your replacement phone can ONLY be the same phone that broke on you. You cannot use the Asurion insurance to get a different phone than you originally had.

As already mentioned, the Motorola warranty does NOT cover just about anything. It only covers issues that should NOT have occurred with the phone under normal usage by the customer. For example, if the phone is constantly freezing on you and/or the power button has stopped working... then you are eligible for warranty replacement as long as you didn't void the warranty by installing unsupported firmware or anything like that. On the other hand, if you take your phone and throw it at the wall and the screen gets a huge crack down the middle.... then that is not supported by the warranty (but it is supported by insurance).

Bottom line, NEITHER type of coverage will allow you to replace your current phone for a completely different brand (or even same brand but different model) phone. I have heard about some of the Droid 1's being replaced with Droid 2's under the Motorola warranty (not insurance)for certain people. But that is just simply great luck and I am pretty positive it isn't something you can have done by request (but rather, I think it is just something being done when Droid 1's are out of stock, etc.). Under both types of coverage, you are only able to get the same model phone that is being replaced unless the company decides to upgrade you to a better version of the same phone (which I've never heard of before until this recent Droid 2 for the Droid 1 warranty replacement).

Since Blackberries are made by Research in Motion (RIM) and Droids are made by Motorola/HTC, you definitely won't be able to get a Blackberry under any Droid warranty. Even under the Asurion insurance, as I mentioned above, I am pretty much positive you wouldn't be able to get a Blackberry in place of your Droid. Asurion will only replace the broken/stolen/lost phone for the same exact model that you currently have.

Sorry to be the bearer of bad news... but I can't see any feasible way to get a Blackberry in place of your Droid aside from simply buying one. Unless there is some other secret method to do it that I'm not aware of... but I really don't think there is lol.